First of all, it is worth mentioning that HVAC gauges are not useful only for heating, air, refrigeration, and air conditioning technicians. Your set of HVAC gauges may help you as much as they help the professionals in charge of the service and/or maintenance of your HVAC unit. Overall, HVAC gauges are used mainly to read the pressure of gases and liquids that are within your cooling system. They also read the vacuum pressure when you charge, or pressure test the device.
Moreover, these gauges come with several ports that determine how many and what type of accessories you can attach to your HVAC unit. Given that these ports also determine the pressure that your gauge can withstand, it goes without saying why you need the best HVAC gauge out there.
In the following lines, we’ll tell you everything that you need to know about this item, and we’ll provide you with several HVAC gauge reviews that will certainly help you find the best fit for your unit!
HVAC Gauges – What Exactly Are They?
Now that we’re all done with the reviews, it’s time to move on to the in-depth buying guide that we’ve accustomed you with!
We realize that you may not like our recommendations – even if they’re the best. So, we’ll do our best to provide you with all the information you need to make a wise purchase when you go out shopping for HVAC gauges.
So, let’s start with the most important thing – what exactly are HVAC gauges?
Basically, HVAC gauges represent a special tool that helps technicians take all sorts of readings. They can perform a variety of tasks – such as pressure readings, testing, vacuuming, recovery, and adding refrigerant.
For example, if you had to replace the refrigerant in your AC system, you or your technician must have a set of HVAC gauges – or else the job can’t be done properly.
Every HVAC gauge set comes with low-pressure and high-pressure sides, as well as on and off valves that you can use to engage in various HVAC operations.
Features and Specifications Every HVAC Gauge Should Have
- Brass or aluminum body for endurance and durability
- High-pressure hoses with at least standard fittings
- Silicone dampened gauges are recommended, but not mandatory
- The gauges should be color-coded
- The gauge set should come with a sturdy suspension hook
- A sighting glass is recommended
- The hoses should come in a decent size – around 60’’
- The HVAC gauge should be able to analyze a wide variety of refrigerants – or at least the industry’s standards
- Superheating and subcooling features
- Angled handles – they make the HVAC gauge much easier to use
Overall, the HVAC gauge must be equipped with what you need to get your job done. This also implies a bit of research before actually buying a set.
For example, you’ll have to check your AC unit’s refrigerant type and such. Eventually, you must make sure that the gauge set you buy fits with the things that you need serviced or checked.
Best HVAC Gauges Comparison Chart
Mastercool 59161 Brass 2-Way Manifold Gauge Set
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Fieldpiece SMAN360 3-Port Digital Manifold with Micron Gauge
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Yellow Jacket 42006 Series 41 Manifold
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Testo 0563 1550 Digital Manifold Kit, Bluetooth Supported
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BACOENG Vacuum Pump & Manifold Gauge Set – Refrigeration Kit
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Robinair 48510 R134a Aluminum Manifold Set
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Best HVAC Gauges – (Recommended Picks)
1. Mastercool 59161 Brass 2-Way Manifold Gauge Set
One of the products on our list is the manifold gauge set from Mastercool. This particular set is designed, tested, and assembled entirely in the US. As such, the product’s brass body is heavy-duty forged in order to ensure the endurance and durability of the gauge set.
The piston-type valves of the set are free-floating, a fact that allows for less friction as well as less internal wear and tear. As a result, the life of the product’s internal O-rings is extended.
This manifold gauge set also comes equipped with high-pressure hoses – grade 5 level – with standard fittings of ¼’’ SAE. These hoses use rubber of the highest technology, are highly flexible and come with little to no risk of kinking.
Lastly, the three gauges are silicone dampened and measure 1/8’’. They are specially designed to smooth out the movement of the needle. Moreover, the R22, R410a, and R404a are color-coded, making it easier to identify refrigerant.
- Reportedly, these gauges are very easy to read
- Great value for money
- Heavy-duty forged brass body
- Lack of quick connects
2. Fieldpiece SMAN360 3-Port Digital Manifold with Micron Gauge
With this product from Fieldpiece, HVAC technicians won’t need to rely on manual calculations or guesswork. This is because this particular item is not only digital but also able to calculate target superheat properly.
The digital manifold comes equipped with a built-in micron gauge that features a resolution of 50 and up to 9,999. This feature comes in very handy when paired with the micron alarm that you can set when using the manifold. You just choose a micron level and the gauge’s alarm will sound when the vacuum reaches that level.
Moreover, the SMAN series of manifolds is able to perform a linear adjustment of the unit’s pressure sensors. This adjustment is based on temperature, refrigerant type, and pressure. On top of that, the adjustment can be done in the field, as it is very easy to accomplish.
- A clear view of measurements
- Micron vacuum gauge with a rate indicator, alarms, and stopwatch
- Subcooling and superheat
- Great value for money
- The screws that hold the clamp mounts can fall out easily
- Lack of multi-meter
3. Yellow Jacket 42006 Series 41 Manifold
This manifold gauge from Yellow Jacket is part of the 41 series that comes with color-coded gauges that are larger than previous models and much easier to read. The manifolds are adorned by rugged steel cases that feature polycarbonate crystals.
In terms of performance, the product comes with Class 1 accuracy – 1% accuracy. This means that it can provide you with an exact reading when it comes to critical charge systems.
Moreover, to reduce the wear and tear of the manifolds, their double O-ring pistons are slidable. Overall, the gauge comes with nylon seats, a forged brass body that enhances durability, and a full porting feature that maximizes flow and capacity.
- Color-coded scales
- Long-life nylon seats
- Hoses with standard fittings
- Very easy to read
- Great value for money
- Some complained about the lack of a sight glass
- Hoses don’t have low loose ends
4. Testo 0563 1550 Digital Manifold Kit, Bluetooth Supported
The Testo 1550 is a digital manifold that is specially designed for a precise display of subcooling and superheat – and that for roughly 60 refrigerants. On top of that, it also comes with features that make it versatile enough to be used in any HVAC job.
The best features of this product are the 2-way valve block that comes equipped with three connections, the Refrigeration App that updates the refrigerant profiles, the ability to measure the low and high side of temperatures and pressures, and the ability to display evaporation and saturation temperatures as well.
Moreover, the digital manifold comes equipped with a suspension hook, with a handy service case, batteries, and two temperature clamp probes.
Last but not least, the gauge itself is protected by a rugged housing that features a hardened metal frame. This ensures the protection from impacts, vibrations, or any other type of moderate damage.
- Comes with two temperature clamp probes
- 2-line backlit display
- High flexibility
- Fairly easy to use
- Bluetooth and app integration for report generation, monitoring, and report export
- The suspension hook is reportedly very fragile
5. BACOENG Vacuum Pump & Manifold Gauge Set – Refrigeration Kit
As you may have guessed, this set comes not only with a manifold gauge set but also with a vacuum pump. In short, it is specially designed for HVAC technicians that look for a set of tools to get them started on the job.
The gauge set is a 2-valve manifold that’s equipped with a sight-glass and with SAE fittings of 1/4’’. The product’s body is made from an anodized aluminum block. Moreover, the aforementioned sight-glass is oversized to ensure easy viewing.
The vacuum pump is labeled as portable and has a flow rate of 3.6CFM, power of ¼ HP, and can create an ultimate vacuum of 0.8Pa.
In terms of accessories, the refrigeration kit comes with three blue, red, and yellow 4ft refrigerant hoses, two ¼’’ SAE male to 5/16’’ SAE female adapters, one toolkit, 12oz of vacuum oil, and one manual for the manifold gauge and pump.
- Multi-function dial – pressure and temperature displayed
- Class 1.6 reading accuracy
- Anodized aluminum block body
- Oversized sight-glass
- Reportedly the gauges are not that accurate
- Lack of R134A fittings/ additional couplers
6. Robinair 48510 R134a Aluminum Manifold Set
We also have a manifold set from Robinair. The manifolds of this particular set are made of aluminum in order to increase their durability. On top of that, they also come with a sight glass so that you can see exactly what’s going on when using this product.
For ease of identification, the manifolds’ handwheels are color-coded, as well as contoured in order to ensure an easy grip. The manufacturer has also improved the face seal valves and gave the product an overall better design to ensure less wear, a tighter seal, as well as improved flow.
The double O-ring piston comes with a special design that provides longer service life and extra reliability. The gauges are easy to read, measure 3-1/8’’, and are protected by highly durable Lexan lenses.
- 90-degree manual couplers
- Blow-molded carry case
- ACME fittings for holding hoses
- Aluminum construction
- Sight glass
- Lack of rubber protectors around the gauges’ dials
7. XtremepowerUS 4 Way Manifold Gauge Set R134A HVAC
Our last entry is a manifold gauge set designed for R22, R12, R410A, and R134A refrigerants. The set features a professional 4-ways design, suited for recovery work, AC charging, and diagnostic check.
The gauges are silicone-dampened in order to provide the set with increased protection against the wear and tear caused mainly by vibrations. On top of that, the gauges are equipped with clear plugs that allow fine-tuning when needed.
This particular product can handle a burst pressure of 4000 PSI and has a maximum working pressure of 800 PSI. Lastly, it comes equipped with a red and blue charging hose of ¼’’x 60’’ and a yellow charging hose of 5/8’’ x 60’’.
In terms of usability, the manifold features a hook that allows easy attachment to surfaces/ledges. The product’s body is made of heavy-duty aluminum, ensuring durability, as well as ease of carrying.
- Color-coded hoses
- Shut off valves
- Quick disconnect feature
- Sight glass
- Heavy-duty solid brass connections
- Great value for money
- The low-pressure gauge may be hard to read
The Inner Workings of an HVAC Gauge
Depending on your understanding of a refrigeration system, HVAC gauges may seem either complicated or easy to understand.
However, the essential part is that you have to learn the components of an HVAC gauge if you want to know exactly how it works. Therefore, let’s take a look:
The Gauge Manifold
The first component of an HVAC gauge is the gauge manifold and can serve as both a service and diagnosis equipment. This particular component has three chamber devices – a high-pressure chamber, a low-pressure chamber, and a utility chamber.
The chambers mentioned above allow you to control the pressure and flow of gas. The two pressure chambers are used to read and stabilize the pressure within the AC unit, for example, while the utility chamber is used to add more refrigerant to the AC or to connect a vacuum pump to it.
The Readout Gauges
Every HVAC gauge comes with two readout gauges. These will display the information provided by the high-pressure and low-pressure chambers.
However, there are brands and manufacturers that add a third gauge, usually for the measuring of the compressor’s output.
Readout gauges can be either digital or analog – an aspect that we’ll be talking about later on.
The hoses that come with the HVAC gauge sets carry pressurized gas. They are usually color-coded so that you know which one has high pressure and which one has low pressure.
The red hose marks pressure between 99.9 and 999 PSI and the blue hose marks pressure between 0 to 99.9 PSI.
As mentioned above, HVAC gauges are used for more than just one operation. This fact changes how they work almost every time. However, overall, gauges read the pressure within HVAC units via hoses, display that information via readout gauges, and help you service your unit safely.
How Do You Buy the Best HVAC Gauge?
Knowing what an HVAC gauge is and how it works is the easy part. Things get quite difficult when it comes to buying a set that would fit you and your needs. For example, in the reviews part, we’ve mentioned that some of those HVAC gauges don’t come with a sight glass.
For someone with experience in the field, a sight glass is much appreciated as it helps them orient better when working. However, if you just want to service your AC unit and don’t know how to use an HVAC gauge, then you will do just fine without the sight glass.
What we mean is that you should know what questions you should ask or what things to consider before you buy an HVAC gauge.
How durable is the HVAC gauge set?
The best HVAC gauge sets are made from metal – usually brass or aluminum, such as the product we’ve mentioned above. Because of this, most of them are usually prone to rust.
However, the metal shouldn’t be the only deciding factor. While you should always choose an HVAC gauge that is made from heavy-duty metal, you should also take a good look at the build quality of the connector fittings, as well as at the hoses.
You should avoid fittings made from plastic as they are known to develop leaks and wear out much faster.
How user-friendly is the HVAC gauge set?
User-friendliness is a big deal, especially if you are not a technician and just want to service your AC unit on your own. If you are a beginner, then the manifold gauge of your choice should be rather easy to connect and must come equipped with quick coupling capabilities.
Naturally, the gauge should be color-coded so that you will never risk mistaking the low-pressure side for the high-pressure one.
If the HVAC gauge set that you buy is hard to use, you risk experiencing leakages, improper connection, as well as possible damage to your AC or refrigerating unit. Therefore, it is important to know how to use an HVAC gauge manifold.
Does it come with any useful extra features?
Gauges and hoses are basic and essential – you should always get those, with any HVAC gauge set that you buy. But this is not everything that you may enjoy with a proper manifold set.
As mentioned above, you may want a model that features a sighting glass, for easier viewing and reading. On top of that, most technicians say that a can tap is recommended for any HVAC gauge set.
Last but not least, you should check the adaptors they feature. You may need a gauge set that is either fitted for R-134A units or that comes with adapters that let you convert the gauge for the mentioned type of units.
Should I buy an HVAC gauge with accessories or accessory compatibility?
In terms of accessories or compatibility, you can get HVAC gauges that can be connected to more than just your AC unit. For example, a manifold gauge can come with one extra port that can fit an HVAC vacuum pump, thus making the service procedure of your AC system much easier.
On the other hand, it is highly recommended that you buy an HVAC gauge that’s part of a set – this includes fittings, hoses, and any other things that you don’t want to look for after you’ve bought the gauge.
Remember to Consider Usability
Obviously, you have to think about the number of uses that you will eventually get out of the HVAC gauge. If you plan on using it only on the AC system within your home, then you don’t have to spend a lot of money on a high-end product.
For example, if you regularly check your units with the help of HVAC refrigerant leak detectors and want to fix them, then an expensive HVAC gauge will do the job as good as a beginner gauge.
Remember to Consider the Budget
Naturally, a beginner should buy an entry-level gauge, while a professional should aim for something more complex.
However, there are cases when beginners buy high-end products, thinking that they make a long-term investment and avoid the replacement of an entry-level HVAC gauge.
The truth is that you should first get accustomed to a simpler, easier to understand gauge, and then move to more complicated products. For example, instead of buying a digital gauge just because it comes with a backlit screen and you have your AC unit in a dark place, you should simply get an analog gauge and pair it with the best UV light for HVAC that you can find.
Steps to Follow when Installing and Using HVAC Manifold Gauges
So, you’ve bought your first HVAC manifold gauge set and are ready to install and use it – even if you just want to test it. Just like with the previous entry in this article, you need to know exactly how to install an HVAC gauge, or else you risk damaging your AC unit.
Luckily, we’re here to help you!
- Begin by connecting the high-pressure side of the unit’s cooling line to the red port on the HVAC gauge. These are the two high-pressure gauges and you have to connect them with a code-approved red hose, specially designed to withstand high pressures.
- Then, connect the low-pressure side to the blue port of the gauge. Naturally, the low-pressure side will be connected to the blue pressure gauge and the low-pressure side of the AC unit via a blue, low-pressure hose.
- Lastly, attach a vent or waste hose to the center of your manifold setup. If you plan on discharging a unit or to vent freon via attaching the unit, then you will need a larger low-pressure hose at the center port of your manifold. Doing so will help you attach a bottle meant to recover refrigerant from the unit, thus preventing its escape into the atmosphere – if the latter happens, keep in mind that it implies breaking federal law.
- Other gauges or micron meters can now be attached to any additional ports. These ports can usually fit vacuum pressure gauges or even vacuum pumps and help you repair the cooling system.
These are the basics of using an HVAC gauge. No matter the job that you have to do, you’ll usually have to connect the ports and hoses in the exact same way. When it comes to other accessories or uses of the HVAC gauge that imply the use of additional ports, then you might have to do some extra steps.
However, keep in mind that the high- and low-pressure ports and hoses will always be connected the same. Doing otherwise comes with a high chance of leakages, wrong readings, and damages to your HVAC unit.
The Essentials of Reading an HVAC Gauge
When it comes to using an HVAC gauge, keep in mind that analog readings are not done in the same way as digital readings. This is mainly because analog HVAC gauges must be calibrated before you read any values.
Therefore, in order to properly read an HVAC gauge, it is better if you know how to calibrate an analog one rather than relying on the fact that everybody uses digital HVAC gauges – because it’s not true.
- To calibrate analog HVAC gauges, you first have to remove the hoses from the chambers.
- Then, you’ll have to open the high and low valves of the HVAC manifold gauge.
- You will see the calibration screws as soon as you remove the gauges’ protective covers.
- Any required adjustments are made via the screws, while the sides can be tapped in order to change the needle’s position. The latter must be on zero. Obviously, you’ll have to refer to the gauge’s user manual when it comes to the adjustments that you have to make.
But how exactly do you read HVAC gauges?
Most HVAC technicians state that once you know what you should be looking for, reading such gauges is a piece of cake! Let’s see what they mean!
First of all, keep in mind that your main focus is on the hand valve, as via its closing and opening you control everything – in terms of HVAC gauge and AC unit.
In order to open the hand valve, you’ll have to rotate the small needle that is located on your HVAC assembly – clockwise to open; counterclockwise to close.
Then, you will have to apply the calibration process we’ve detailed above. Namely, remove the hoses from the chambers, open the valves, and adjust the calibration screws.
After making sure that the needle starts at zero and that the calibration is complete, you can be sure of the readings displayed by your HVAC gauge.
Things to Consider When Faced with Analog and Digital HVAC Gauges
As we mentioned a couple of times before, we have to talk about the main types of HVAC gauges – namely analog and digital gauges.
Also, we have to point out the reasons why a lot of HVAC technicians don’t feel like switching to digital gauges, even if most people claim that they are more accurate and overall better when it comes to readings.
Analog HVAC Gauges
Analog gauges come with the good old, trusty indicator needle. Obviously, such gauges are the most common type of HVAC gauges that can be found on the market.
You read an analog gauge by looking at the needle’s position. It will show you the level of pressure or vacuum that’s inside your AC or other refrigerating units.
Overall, analog gauges are easy to use but are prone to errors. On top of that, even after you learn the basics of HVAC gauges, you may still have issues when it comes to pressure conversions.
Digital HVAC Gauges
These modern gauges provide you with pressure and vacuum readings in numerals. As expected, the main advantage they come with is that they’re more accurate than the analog HVAC gauges.
Moreover, digital gauges, come equipped with extra features that make the work of an HVAC technician a lot easier. For example, they automatically convert readings, reducing the risk of errors.
However, many HVAC technicians are fairly new to this tech and are not keen on learning it. Most of them would rather rely on their experience with analog gauges than learn how to use a digital one.
The Pros of Analog HVAC Gauges
- Have been used for a long time and stood the test of time
- Are a tried and true method
- HVAC technicians could easily tell what pressures a certain unit should be reading without checking a chart
The Cons of Analog HVAC Gauges
- Are prone to errors
- Provide the technician with a rough picture only
The Pros of Digital HVAC Gauges
- Highly accurate
- Come with a plethora of other features
- Reduced risk of errors
The Cons of Digital HVAC Gauges
- They are pricier than analog gauges
- Heavier and usually less durable
- Require training, mainly due to features added by manufacturers that make them difficult to use
Overall, it is the personal preference that comes into play when you have to choose between an analog or digital HVAC gauge. If you are not a technician and will mainly do routine repairs or service, then you can trust an analog gauge.
On the other hand, if you are a professional in the industry and have to deal with more than simple service or maintenance works, then a more accurate gauge will help you do your job much better.
Answers to the Questions You May Have
- How to make sure that I never mistake one pressure valve for the other when using an HVAC gauge?
First of all, you can tell valves apart via their colors. As mentioned above, the low-pressure valve is always blue and the high-pressure valve is always red. For example, if you have replaced valves or use hoses that are not color-coded, you still don’t have anything to worry about.
Why? Well, because the dimensions of the two pressure valves are also different. You will not be able to fit a high-pressure hose into a low-pressure valve.
- Can I use the same HVAC gauge on all AC/ HVAC systems?
As we mentioned earlier, compatibility is one significant issue when it comes to HVAC gauges. All HVAC systems are different. Therefore, you must have gauges that fit with your system – or with the system that you want to work on.
One way to make sure that a manifold gauge fits most systems is to choose a 4-way model. However, even when you buy a 4-way model, you’ll still need adapters and different fittings, especially if you are a technician.
- Are there any other helpful tips that I should know?
Naturally, there are always new things and tips that you can learn about a certain system or tool.
When it comes to HVAC gauges, keep in mind that the center part of the manifold is not useless. This is where you connect the waste or vent hose, in case you are removing refrigerant out of a unit.
Moreover, your HVAC gauge can come with more than three ports, depending on what features you want it to have. For example, you may have additional ports for attaching vacuum pumps, micron meters, and so on.
- What is the ideal low and high pressure that my HVAC gauge should display?
This is the most common question asked by those who’ve just bought their first HVAC gauge. So, let’s answer your question!
The ideal high pressure should be roughly 50 PSI, while the ideal low pressure of your AC system should be around 30 PSI. Low pressure, despite being ignored by a lot of people, is almost as important as high pressure.
You should take the appropriate steps if the pressure is lower than 30 PSI.
Now you know how you can find the best HVAC gauge on the market! All you have to do is consult with our buying guide, as it provides you with everything that you should know about a manifold gauge before buying one.
Moreover, if you just want to buy one as soon as possible, simply check the HVAC gauge reviews of the best seven gauges we could find on the market – you won’t be disappointed!
Overall, HVAC gauges are not that complicated. You just need to know what they do, how they work, and how to read them properly. For all of the other things, you can refer to a user’s manual. However, most technicians claim that, after a couple of successful uses, anyone can get the hang of an HVAC gauge!